• Journal of Korean society of Dental Hygiene
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• v.13 no.4
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• pp.543-552
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• 2013

Objectives : The aim of the study is to investigate job performance expectations according to duration of work and to specify the clinical practice of dental hygienists by career expectations. Methods : The subjects were 310 dental hygienists in Seoul and Incheon. They completed the self-reported questionnaires and 304 data were analyzed except incomplete 6 answers. Results : The tasks performed by dental hygienists were as follows ; SS crown restoration in pediatric dentistry accounted for 25.1%, orthodontics (42.1 %), plaque removal (71.4 %), temporary fillings (60.5%), and impression taking of abutments and bite registration (58.9%). In order to be a skillful dental hygienists, it took two to three years of clinical filed work. Conclusions : On the job training (OJT) is the most important in dental hygiene curricula. So it is necessary to develop the OJT performance skill.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.4
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• pp.317-323
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• 2018

When oral cancer develops in the maxilla, oro-nasal communication occurs after surgical treatment including removal of the primary site. Restoration through an obturator is necessary to prevent food from storing due to non-oral opening, and to ensure proper pronunciation and aesthetic restoration. In this case, the patient was treated with right hemi-maxillectomy due to oral cancer and has residual abutment and poor periodontal support due to the effect of head and neck radiotherapy. The obturator was treated with a hybrid telescopic double crown denture. Reporting a successful prognosis in 18 months of follow-up.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.13.1-13.6
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• 2020

Background: The aim of this study was to evaluate the factors that may affect implant fixture fractures. Methods: Patients who experienced implant fixture removal at Seoul National University Bundang Hospital from 2007 to 2015 due to implant fixture fracture were included. Implant/crown ratio, time of implant fracture, clinical symptoms before implant fracture, treatment of fractured implants, and the success and survival rate of the replaced implants were evaluated retrospectively. Results: Thirteen implants were fractured in 12 patients. Patient mean age at the time of fracture was 59.3 years. Of the 13 implants, 7 implants were placed at our hospital, and 6 were placed at a local clinic. The mean crown/implant ratio was 0.83:1. The clinical symptoms before fracture were screw loosening in five implants, marginal bone loss in five implants, and the presence of peri-implant diseases in five implants. All the fractured implants were removed, and 12 out of the 13 sites were re-implanted. Parafunctions were observed in two patients: one with bruxism and one with attrition due to a strong chewing habit. Conclusions: Several clinical symptoms before the fracture of an implant can predict implant fixture failure. Therefore, if these clinical symptoms are observed, appropriate treatments can be taken before more serious complications result.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.4
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• pp.359-365
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• 2014

Successful results of treatments using double crown prostheses for the partially edentulous patients who have a few remaining teeth have been reported in several journals. A double crown removable partial denture can be an alternative treatment for the patients with a poor periodontal condition of remaining teeth. Since a double crown removable partial denture can be applied without the risk of surgical operation to the medically compromised patients with a poor periodontal condition which is inadequate for dental implants, it has psychological and economical advantages. In this case, there were sufficient remaining teeth to be restored with fixed prostheses in maxilla, while there were a few remaining teeth with a very poor periodontal condition so that it was almost impossible to restore with a clasp removable partial denture using these remaining teeth in mandible. In addition, the patient had the medical history of surgical operation due to osteomyelitis in the mandibular anterior areas a year ago, thus difficult to conduct an implant placement. The main objective of this report is to introduce our case because a double crown partial denture using a few mandibular remaining teeth showed satisfactory results in functional and esthetical aspects during more than two years follow-up period in this unfavorable condition.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.2
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• pp.201-209
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• 2021

In removable partial dentures, many types of retentive systems have been studied and applied in clinical treatment. One of those systems is the double crown denture system which is widely used in European countries such as Germany and Sweden. Telescopic double crown dentures have several advantages such as convenience in maintaining oral hygiene, enabling to transfer occlusal force along the long axis of the abutment, and secondary splinting effect between the abutments which leads to higher clinical performance compared to conventional removal partial dentures. In this clinical case, the patient was initially restored with a maxillary hybrid telescopic double crown denture with friction pin using remaining natural teeth as abutments. After 7 years, due to lack of recall check-up and poor oral hygiene, the abutment teeth were affected by periodontitis and 4 out of 5 of the abutment teeth had to be extracted. 3 additional implants were placed and the original abutment tooth with the inner crown was maintained. The mandible had fixed prostheses including implants but nevertheless, with strategic implant placement, the patient adapted well and was satisfied with the new maxillary tooth-implant combined double crown denture.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.1
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• pp.103-121
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• 1989

The purpose of this study was to investigate the influence of balancing interference on the activity of masticatory muscles and condylar path. Eight dental students of Won Kwang University without any symptoms of temporomandibular disorder and occlusal interferences, were selected for this study, The balancing interference was provided by construction and cementation of cast metal crowns on the upper and lower first molars. For the measurement of muscle activity, bioelectric processor (EM2, Myotronic Res., Inc., U.S.A.) was used and for the condular path, computerized electronic pantograph (Pantronics, Denar Corp., U.S.A.) was used and the myographic recordings were taken bilaterally from the anterior temporal, masseter and digastric muscles on rest position and on functions. These experimental procedures were done before cementation of experimental crown, three days after cementation of experimental crown, one week after, two weeks after and then one week after removal of experimental crown. The results are as follows: 1. The PRI score was increased at three days after application of balancing interference, and decreased at two weeks after. 2. Three subjects showed mild symptom of temporomandibular disorder at three or four days after application of interference, but the symptom was subsided in one or two weeks after application of interference. 3. One week after application of balancing interference, the activity of ipsilateral anterior temporal muscle in four subjects was decreased on gum chewing at experimental site. 4. Three days after application of balancing interference, the activity of ipsilateral anterior temporal muscle in three subjects was increased on gum chewing at non-experimental site. 5. The influence of balancing interference on the activity of anterior temporal, masseter and gigastric muscle was not prominent.

• Journal of Periodontal and Implant Science
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• v.26 no.1
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• pp.293-308
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• 1996

Recently, dental laser have been applied for removal of soft tissues, hemostasis and blood coagulation, removal of benign and malignant tumor, treatment of leukoplakia, aphthous ulcer and herpetic lesion, implant second surgery, removal of granulation tissue, frenectomy, clinical crown lengthening, gingivectomy, gingivoplasty, and treatment of dentin hypersensitivity. Even though the frequency of laser treatment is increasing, the research on the healing process after gingivectomy using pulsed Nd : YAG laser is very rare. The purpose of this study was to observe and compare the wound healing after gingivectomy using scalpel and pulsed Nd : YAG laser in the rat. Gingivectomy was performed using pulsed Nd : YAG laser(SUNRISE Technologies, U.S.A., 1.5 Watts, 10 pps) on the buccal gingiva of right maxillary first molar and using scalpel(No.12) on the contralateral side. Those sites treated by surgical scalpel were designated as the control, and by pulsed Nd : YAG laser as the experimental group. Animals were sacrificed at 1, 2, 3, 5, 7, 11 and 14 days postoperatively, and specimens were histologically observed under light microscope. The results were as follows : 1. Clinical observation Normal color and shape were observed at the 5th day ill the control group and the 7th day in the experimental group. 2. Histologic findings 1) In the control group, denser inflammatory infiltration was observed. 2) Epithelialization started at the 2nd day in the control group, similar to the experimental group, and completed at the 11th to the 14th day postoperatively. 3) In the experimental group, connective tissue showed the vacuole formation and degenerative change during early healing period. Healing of connective tissue was slower in the experimental group than in the control group by 2 days. 4) In the both groups, wound healing was completed at the 2nd week. From this study, gingivectomy using pulsed Nd : YAG laser seems to result in a little delayed wound healing process, compared to the gingivectomy using scalpel. Considering the clinical advantages of laser surgery, pulsed Nd : YAG laser might be useful device for gingivectomy.

• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.4
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• pp.293-302
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• 2007

I. Objectives The purpose of this study was to compare the shaping ability between the single length technique performed with Mtwo instruments (VDW, Munich, Germany) and the crown-down technique using K3 (SybronEndo, West Collins, CA, USA) and RaCe (FKG, La Chaux-de-Fonds, Switzerland) instruments. II. Materials & Methods Forty five curved canals in resin blocks were equally divided in to three groups. Group 1 (Mtwo) was instrumented used the full length of canal according to the manufacturer's instructions. The simulated canals was prepared to an instrument size of 35, 0.04 taper canal terminus. In group 2 (Race) and group 3 (K3) was instrumented in a crown-down manner and prepared to an instrument size of 30, 0.06 taper canal terminus. Pre- and post-instrumentation images were scanned and assessment of canal shape was completed with a computer image analysis program. Material removal was measured at 7 measuring points, beginning 1mm from the end point of preparation. Differenced of centering ratio were statistically analyzed using One-way ANOVA followed by Duncan's test. II. Results & Conclusion There was no significant difference on 1, 2, 3 and 7mm measuring point. At 4 and 5 measuring point, significant difference showed between the Mtow instruments and other two instruments. (p<0.05)

• Proceedings of the KOR-BRONCHOESO Conference
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• 1981.05a
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• pp.12.1-12
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• 1981

The dentigerous cyst originates through alteration of the reduced enamel epithelium after the crown of the tooth has been completely formed, with accumulation of fluid between the reduced enamel epithelium and the tooth crown. The dentigerous or follicular cyst comprises about 20% of all dental cysts. It usually occurs between 20 and 30 years of age but is occasionally seen in children or in old people. The most common sites of this cyst are the mandibular third molar and maxillary cuspid areas, since these are the most commonly impacted teeth. Many of these cysts give no clinical symptoms until noticeable asymmetry of the face develops. Rarely it develops to an ameloblastoma, epidermoid carcinoma and mucoepidermoid carcinoma, so early removal leads to better result. Roentgenographic examination of the jaw involved by a dentigerous cyst will reveal a radiolucent area. Recently the authors have experienced a giant dentigerous cyst which produced the bony deformity of the maxillary and hard palate bone. The cyst was completely removed under the local anesthesia by Caldwell-Luc approach.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.457-463
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• 2001

In the unconscious patient with general muscle rigidity, the natural teeth can be luxated and then bite wounds may be occurred around lip, owing to the pathologic involuntary self-biting habit. If the forceful biting is generated continuously, the teeth may be avulsed and aspirated into the aerodigestive tract with the infection of biting wound. For the prevention of pulmonary aspiration of the teeth and wound infection, the biting teeth should be cared before the fact. The authors treated the teeth as endodontic drainage with removal of the crown or iodoform gauze drainage into the socket with extraction of the teeth. The prognosis was more favorable without biting wounds.